The intestinal absorption of separately labeled simple and conjugated folates has been measured by the technique of jejunal perfusion in normal subjects and in patients with tropical and celiac sprue. Subcellular fractionation and enzyme purification techniques are use to dentify a surface active (brush border) folate conjugase enzyme in human jejunal mucosa. The effect of alcoholism on folate absorption and metabolism is measured in patient volunteers by the jejunal perufusion method, and in non-human primates (Macaque Radiata) pair fed a liquid diet containing 50 percent of calories as ethanol. BIBLIOGRAPHIC REFERENCES: Halsted, C.H., Reisenauer, A.M., Back, C., Gotterer G. In vitro uptake and metabolism of pteroylpolyglutamate by rat small intestine. J. Nutr. 106:485-492, 1976. Corcino, J.J., Reisenauer, A.M., and Halstead, C.H. Jejunal perfusion of simple and conjugated folates in tropical sprue. J. Clin. Invest. 58:298-305, 1976.